Safety razors

ABSTRACT

A safety razor having one or more blades seated between a cap and guard, said guard cap and guard having a comb-like configuration in which a comb-like moulding of a mixture of polyethylene oxide and a structural polymer, such as polystyrene, is positioned between the teeth of the comb-like cap portion, the teeth of the polyethylene oxide-containing moulding being narrower than the space between the teeth of the cap portion so that the blade unit can flex concavely.

SAFETY RAZORS

This invention is concerned with safety razors which comprise a flexiblerazor blade unit secured to a handle by connecting means arranged topermit flexure of the unit when the razor is used.

BACKGROUND OF THE INVENTION

The blade unit is flexible in the sense that it is readily flexible, inresponse to forces encountered during normal use, about an axis or axesparallel with the plane of the blade unit and extending substantiallyperpendicular to the cutting edge(s) of the blade(s). Safety razors ofthis kind are described for example, in British Specifications 1589591and 2119690.

One form of blade unit for such a safety razor comprises a flexibleblade or tandem flexible blades with a flexible spacer therebetween,which blade or blades and spacer are mounted in a moulded plasticshousing providing a comb-like guard portion and a comb-like cap portion,the teeth of the two comb-like portions being interconnected by a webwhich is sufficiently thin to be flexible. The blade unit is connectedto a razor handle by connecting means which permit flexing of the bladeunit in use.

SUMMARY OF THE INVENTION

We have now developed an improvement of such a safety razor in which acomb-like moulding of a mixture of polyethylene oxide and a structuralpolymer, such as polystyrene, is positioned between the teeth of thecomb-like cap portion, the teeth of the polyethylene oxide-containingmoulding being narrower than the space between the teeth of the capportion so that the blade unit can flex concavely.

According to the present invention, there is provided a safety razorwhich comprises a razor blade unit which is readily flexible, inresponse forces encountered during normal use, about an axis or axesparallel with the plane of the blade or blades and extendingsubstantially perpendicular to the cutting edge(s) thereof, a handle,and connecting means connecting the blade unit to the handle which meanspermit flexing of the blade unit, the blade unit comprising a mouldedplastics housing providing a comb-like guard portion and a comb-like capportion between which the blade or tandem blades with a spacertherebetween is/are clamped, the teeth of the two comb-like portionsbeing interconnected by a web which is sufficiently thin to be flexible,and the blade unit further comprising a comb-like moulding of a mixtureof polyethylene oxide and a structural polymer, positioned between theteeth of the comb-like cap portion, the teeth of the polyethyleneoxide-containing moulding being narrower than the space between theteeth of the cap portion so that the blade unit can flex concavely.

The teeth of the polyethylene oxide-containing moulding are preferablylevel with or project above the teeth of the cap portion.

The use of inserts formed of a mixture of polyethylene oxide and astructural polymer, such as polystyrene, in the cap and/or the guardportions of razors and blade units to improve shaving performance isknown and has been described, for example, in British Specification2024082. Such inserts typically contain, by weight, 80% of polyethyleneoxide and 20% of structural polymer. The present invention provides aparticularly convenient way of incorporating polyethyleneoxide-containing inserts in a flexible blade unit of the kind described.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A currently preferred embodiment of the invention will now be described,by way of example, with reference to the accompanying drawings, inwhich:

FIG. 1 is a perspective exploded view of the razor, and

FIG. 2 is a similar view of the assembled razor.

The illustrated razor comprises a flexible blade unit 10 which comprisesa moulded plastics housing 11 (made, for example, from polystyrene)which has a comb-like guard portion 12 and a comb-like cap portion 13between which a combination of tandem single edged razor blades 14 witha spacer 15 therebetween is clamped. The blades 14 and spacer 15 areretained in the correct position by protrusions (not shown) in thehousing and protrusions (not shown) on the spacer 15 which engage inslots 16 in the blades. Slots are used so as to allow relative movementof the blades and spacer during flexing. The teeth of the comb-likeportions 12 and 13 are interconnected by a web 17 which is sufficientlythin for the blade unit 10 to be flexible.

The blade unit further comprises a comb-like polyethyleneoxide-containing moulding 18, the teeth 19 of which are positionedbetween the teeth of the cap portion 13, the width of the teeth 19 beingless than the space between the teeth of the cap portion (when the bladeunit is unflexed) so that the blade unit can flex concavely.

The teeth 19 of the polyethylene oxide-containing moulding 18 areinterconnected by a web 20 which is adhesively secured to the back ofthe web 17. As can be seen from FIG. 2, in the assembled condition, theteeth 19 of the polyethylene oxide-containing moulding 18 are level withthe teeth 13 of the cap portion.

FIGS. 1 and 2 further illustrate a preferred manner of assembling theblade unit, that is the polyethylene oxide-containing moulding 18 is notseparated from the sprue 21 with which it is moulded until the moulding18 has been bonded to the housing 11; the sprue 21 is then cut away (seeFIG. 2).

The blade unit 10 is connected to a handle 22 by means of three posts23,24 depending integrally from the underside of the housing 11 whichslidably engage in corresponding slots 25,26 in the head of the handle.The posts 23,24 extend perpendicularly to the parallel planes of theblades and are positioned directly underneath the blade edges, i.e.passing through a region bordered by the blade edges. The central post24 is guided for rectilinear sliding movement within the slot 26; thispost therefore centralises the unit longitudinally, without interferingwith its flexure. The outer posts 23 each have a pivot pin 27 projectingthrough them, parallel with the axis or axes of flexure of the bladeunit, and these pins 27 are received in and guided by elongate slots 28formed in the walls of the slots 26, so that they accommodate flexure ofthe blade unit, which is accompanied by movement of the ends of the unittowards and away from each other. The pins 27 also prevent withdrawal ofthe blade unit from the handle.

The posts 23 are set in from the ends of the unit so as to permit theblade unit to flex convexly if one or both ends encounter larger forcesduring shaving than the medial portion of the unit.

In order to protect the blade unit from damage due to excessive flexurein both concave and convex modes it has been found necessary to limitdeflection both at the centre and at the ends of the cartridge.

In the concave mode, deflection from the unflexed plane is limited byabutment of the underside of the platform with the centre of the head ofthe handle. In the convex mode, deflection of the outer portions of theblade unit is limited by abutment of the underside of the outer portionsof the platform with outer portions of the handle head.

In a particular embodiment the concave deflection is limited to 2.5 mmat the centre, and the convex deflection is limited to 3 mm at the ends,of the blade unit. The spacing of the outer posts 23 is preferably 2/3of the overall length of the blade unit.

The main forces encountered during shaving are directed perpendicular tothe plane of the blades (or blade) and passing through a region borderedby the cutting edges of a tandem blade unit. Since the posts 23,24 arealigned with those forces, they do not encounter any substantial bendingmoment which would otherwise tend to tilt them and create a tendency forthe pins 27 to bind in the guide slots 28.

Whilst we have described an embodiment in which the polyethyleneoxide-containing moulding is made separately from the housing 11 and isadhesively bonded to the latter, the polyethylene oxide-containingmoulding can be made in situ by a two stage moulding process, namely aprocess in which different materials are moulded into a single componentby moulding one material first and then moulding the second in situ.This process can be used to mould the housing and the polyethyleneoxide-containing moulding as a single component (spacing pieces beinginserted into the mould before the injection of the polyethyleneoxide-containing mixture to provide the desired gaps between the capteeth and the teeth of the polyethylene oxide-containing moulding. Thiseliminates the need for adhesive bonding and the reduction in theflexibility of the unit which might arise from the use of an adhesive.

I claim:
 1. A safety razor which comprises a razor blade unit having atleast one generally planar blade with a cutting edge, which blade unitis readily flexible about an axis or axes parallel with the plane ofsaid at least one blade and extending substantially perpendicular to thecutting edge thereof;a handle; and, connecting means disposedcooperatively on said blade unit and said handle for connecting theblade unit to the handle which means permits flexing of the blade unit,the blade unit comprising: a molded plastic housing including:a guardportion having spaced apart teeth interconnected by a thin, flexibleweb; a cap portion having spaced apart teeth interconnected by a thin,flexible web; said at least one blade being clamped between said capportion and said guard portion. said blade unit further comprising amolding having spaced apart teeth interconnected by a thin, flexibleweb, said molding including a mixture of polyethylene oxide and astructural polymer, the teeth of said molding positioned between theteeth of said cap portion, the teeth of the polyethyleneoxide-containing molding being narrower than the space between the teethof the cap portion so that the blade unit can flex concavely.
 2. A razoraccording to claim 1, in which the teeth of the polyethyleneoxide-containing moulding are level with or project above the teeth ofthe cap portion.